1. Field of the Invention
The present invention relates to a battery pack that includes a housing, an array of electrochemical cells disposed in the housing, and a force generating assembly disposed in the battery pack between the housing and the array. The force generating assembly applies a force to the array in two orthogonal directions, whereby direct contact, weld-free electrical connections are made between terminals of adjacent cells and/or between terminals of the cells and the terminals of the battery pack.
2. Description of the Related Art
Battery packs provide power for various technologies ranging from portable electronics to renewable power systems and environmentally friendly vehicles. For example, hybrid electric vehicles (HEV) use a battery pack and an electric motor in conjunction with a combustion engine to increase fuel efficiency. Battery packs are also used to power fully electric vehicles including some plug-in electric vehicles. Battery packs are formed of a plurality of battery modules, where each battery module includes several electrochemical cells. The cells may have various housing configurations, including prismatic, cylindrical and pouch. The cells within a module are electrically connected in series or in parallel. Likewise, the battery modules within a battery pack are electrically connected in series or in parallel.
Some conventional battery packs contain cells that are connected together via welding to form an electrical circuit with a bus bar system. Battery control and disconnect devices may also be connected via welding to the cells to the bus bar system. Since battery packs used in vehicles frequently include hundreds of cells, forming the welded electrical connections between each element of the battery system can be labor intensive and costly. Moreover, the bus bars and/or other electrical connectors disposed in the battery pack occupy a relatively large proportion of the space within the battery pack housing, whereby the volumetric efficiency of the battery pack is reduced.